<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        section {
            width: 80%;
            height: 200px;
            background: palegreen;
            margin: 100px auto;
            display: flex;
            /* flex-direction: row; 默认水平排列 */
            /* flex-direction: column;默认竖直排列 */
            flex-direction: row-reverse;
            /* //水平翻转 就是倒过来了 */
            /* flex-direction: column-reverse;垂直翻转 */
        }
        
        section div {
            height: 100%;
        }
        
        section div:nth-child(1) {
            background-color: palegoldenrod;
            width: 200px;
        }
        
        section div:nth-child(2) {
            background-color: palegreen;
            width: 100px;
        }
        
        section div:nth-child(3) {
            background-color: paleturquoise;
            flex: 1;
        }
        
        section div:nth-child(4) {
            background-color: palevioletred;
            flex: 1;
        }
    </style>
</head>

<body>
    <section>
        <div>1</div>
        <div>2</div>
        <div>3</div>
        <div>4</div>
    </section>
</body>

</html>